DISABLE VIBRATE - FB NOTIFICATION

I wonder why such a simple option has been omitted.
Could you make an option that gives more control over FB notifications, wherein we can change/disable notification sound and also enable/disable vibration when getting notifications.

Also, a simple glitch is that even when we're in fb.com's messages, CHATTING with the person, we get notifications. Please fix it so that notifications come only when-
Opera is in background
OR
When we're not in fb.com